LOS ANGELES – A wildfire tearing through a coastal region in Southern California nearly tripled in size as high temperatures fueled the flames, but a fire official said early Saturday that a favorable shift in the weather will likely help crews make progress against the flames.

The fire 50 miles northwest of Los Angeles mushroomed to 43 square miles Friday as 900 firefighters used engines, aircraft, bulldozers and other equipment to battle the flames.

Forecasters said a weekend of increased humidity should help teams fighting the early-season blaze.

"It's a total turnaround from what we had," said Kurt Kaplan, a meteorologist at the National Weather Service in Oxnard. "It should be a much better day for firefighters tomorrow."

Capt. Mike Lindbery of the Ventura County Fire Department said early Saturday that crews intended to take advantage of lower temps and higher humidity.

"That will give us a chance because it's going to really bring that fire activity down quite a bit. I think we will make some significant progress," Lindbery said.

Despite its size and speed of growth, the fire that broke out Thursday and quickly moved through the Camarillo Springs area has caused damage to just 15 structures, though it's threatening thousands.

Residents were grateful so many homes were spared.

""It came pretty close. All of these houses -- these firemen did a tremendous job. Very, very thankful for them," Shayne Poindexter said. Flames came within 30 feet of the house he was building.

Ventura County Fire Department spokesman Bill Nash said parts of the Newbury Park community of Thousand Oaks were under mandatory and voluntary evacuations. Overnight, he said firefighters planned to stockpile resources along a road that lies between the fire and Malibu, protecting homes on the fire's eastern front. Its cause of the fire is under investigation.

The good fortune of the Camarillo Springs area wasn't the result of luck or clairvoyance by firefighters. It came after years of planning and knowing that sooner or later just such a conflagration was going to strike.

Camarillo Springs, which was nothing more than rugged backcountry when homes began to go up there 30 years ago, was well prepared.

Its homes were built with sprinkler systems and fireproof exteriors from the roofs to the foundations. Residents are required to clear brush and other combustible materials to within 100 feet of the dwellings, and developers had to make sure the cul-de-sacs that fill the area's canyons were built wide enough to accommodate the emergency vehicles seen on TV racing in to battle the flames.

Residents in the area are also particularly vigilant about clearing brush from the hillsides next to their yards, Kruschke said. Normally, firefighters remind people in such areas to do that every June, but in Camarillo Springs people do it every few months. The work paid off this week.

The type of blaze that hit the area usually doesn't strike Southern California wild-land until September or October, after the summer has dried out hillside vegetation. But the state has seen a severe drought during the past year, with the water content of California's snowpack only 17 percent of normal.

That created late-summer conditions by May, and when hot Santa Ana winds and high temperatures arrived this week, the spring flames that firefighters routinely knock down once or twice a year quickly roared up a hillside -- out of control.

On Friday, the wildfire stormed back through canyons toward inland neighborhoods when winds reversed direction.

After jumping Pacific Coast Highway 20 miles north of Malibu, the fire burned for a time on a beach shooting range at the Point Mugu Naval Air Station.

The blaze is one of more than 680 wildfires in the state so far this year -- about 200 more than average.

In Riverside County, a 4 1/2-square-mile fire that destroyed a home burned for a third day in mountains north of Banning. It was 75 percent contained.

Fifty-five miles away from Camarillo, in the hills above Glendale, a blaze broke out Friday afternoon, prompting evacuations and closure of a freeway as it quickly charred 75 acres.

In Tehama County in Northern California, the size of a wildfire north of Butte Meadows was revised down from more than 15 square miles to 10 square miles, state fire spokesman Daniel Berlant said.

The fire, which was 20 percent contained, was burning in a remote area and wasn't posing an imminent threat to any structures.